Fuel metering device



Feb. 29, 1944-, s EY ETAL Re. 22,447

| Q FUEL METERING DEVI-CE v I Original Filed April 24, 1940 INVENTOR. bnafd firss x Y/YribqrESmiLb.

. ATTORNEY 1 Reissued Feb. 29, 1944 FUEL METERING nrzvrcr:

Donald S. Hersey, East Hartford, Comm, and Arthur E. Smith, Kansas City, Kana, assignors to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Original No. 2,295,656, dated September 15, 1942,

Serial No, 331,448, April 24, 1940. Application for reissue September 9, 1943, Serial No. 501,720

4-Claims. ((1261-18) 7 v usually occur only in the upper portion of the This invention relates to improvements in engine fuel metering controls and has particular reference to an improved fuel metering device I for an internal combustion engine utilizing explosive charges formed by evaporating fuel in the intake air.

An object of the invention resides in the provision of an improved fuel metering device of the character indicated which is operative to meter a standard fuel to the engine at all times during engine operation and to meter an auxiliary fuel to the engine under certain predetermined engine operating conditions.

A somewhat more specific object resides in the provision of an improved fuel metering device of the character indicated which is operative to supp y a regulated quantity of detonation reducing fuel modifying substance to the engine under engine operating conditions where detonation is likely to occur.

A still further object resides in the provision in an improved fuel metering device of thelcharacter indicated of manually controllable means for causing an injection of the auxiliary fuel into the engine fuel supply as the operator may desire, for-instance at such time as there appears to be a. condition of ice formation in the engine 7 intake.

Other objects and advantages will be more particularly pointed out hereinafter or will become apparent as the description proceeds.

In the accompanying drawing, in which like parts throughout, there is illustrated a suitable mechanical embodiment of a portion of an engine is a longitudinal sectional view of a portion of an engine intake with a fuel metering device,

constructed according to the invention, applied thereto, the drawing being largely diagrammatic in character.

As is well known to those skilled in the operation of internal combustion engines, detonation of the fuel charges in the engine cylinders tends to occur only under particular engine operating conditions and if the fuel used is well suited reference numerals are used to designate similar engine power range. Even with the best fuel. however, in order to obtain good fuel economy it is necessary to operate the engine near the detonation point in the upper portion of the power range and it frequently happens that detonation occurs when the engine reaches the upper part of the range. For example, in the case of an airplane engine, in order to obtain good fuel economy in the cruising range it is necessary to run the engine very close to the detonation point in the take-off portion of the power range. It has been found that the economy can be considerably improved if the engine is run quite close to the detonation point in the cruising portion of the power range, so that it would normally detonate in the full throttle and take-ofi portion of the power range, and then to supply an ingredient'to the fuel during only those portions of the power range in which detonation would occur to suppress the detonation under those particular operating conditions.

If an engine is so adjusted that it will run on ordinary aviation gasoline without detonation except in the take-01f portion of the power range, a small quantity of fuel ingredient of high antidetonation characteristics supplied to the engine only during the take-oil period will provide detonation free engine operation and excellent fuel economy as the take-oil. operation of the engine is a very small fractional part of its total operation. It has been found that an ingredient comprising a mixture of aniline and alcohol is very effective in eliminating detonation in those portions of the power range in which detonation would occur with the ordinary engine fuel and that, by adjusting the engine so that detonation would occur in the take-off portion of the range, for example, on the ordinary fuel and then supplying additional anti-detonating fuel, such as the aniline and alcohol mixture, to the engine during take-off, greatly improved fuel economy and detonation free operation is obtained. Instead .of the additional fuel, -a fuel modifying substance, such as tetra-ethyl lead, or a combination of the two may be used, if desired. It is essential, however, that the additional material should be automatically supplied to the engine the value at which the engine will operate without detonation on the ordinary fuel, as the opto the engine, detonation, if it occurs at will is erator of the engine may not always beable to detect the detonation point and supply the additional material in time to avoid the beginnin of detonation. It has been found that once detonation starts a dangerous loss of engine power can occur before it can be stopped and the engine operation restored to detonation free operation. It has also been found that the auxiliary fuel supplied to suppress detonation can be given excellent de-icing characteristics, particularly if an auxiliary as the alcohol and aniline mixture is used, and the present invention contemplates the provision of means whereby this fuel can be injected into the engine intake system when its de-icing characteristics are needed, as well as for its detonation suppressing purpose;

Referring to the drawing in detail, the numeral l generally indicates the engine vintalcetonduit. In the arrangement illustrated, an engine supercharger impeller I2 is positioned at one end of this conduit and an air flow'measuring Venturl throat I4 is posltioned'at the opposite end. A throttle i6 is disposed in the conduit between the Venturi throat and the impeller and may be operated by a manual control mechanism, as gener-.

cation Serial No. 302,89lfor Fuel supply systems,

filed November 4, 1939, by Richard 5. Buck.

HA casing, generally indicated at 24, is disposed adjacent to the intake ill or secured thereto. and

provided interiorly thereof with two chambers 26 and 28 separated by a valve, generally indicated at 38, and comprising the valve seat 32 and valve gate 34. The chamber 26 is connected by a channel 36 with an annular chamber 38 surrounding the venturi and connected with the interior of the Venturi throat by a plurality of ports 48' and is connected with the'interior of the intake I 8 on the upstream side of the venturi relative to the direction of air flow, by a channel 42. The

chamber 26 is divided into substantially equal' portions by a transverse partition 44 and eachof these portions is substantially equally divided by a transverse diaphragm as indicated at 46 and 48, respectively. From an, inspection of the drawing it. will be observedfithat the channels 36 and 42 both lead to the space on one side of the transverse partition 44 and respectively to opposite sides of the diaphragm 46., A channel 50 through the fuel conduit 28 leads from the space at one side of the diaphragm 48 to the nozzle 22 and a second channel 52 leads from the space at the opposite side of the diaphragm 48 through a restrictedorlfice 54 to the channel 56. The diarelation ona shaft 56 which extends through an the measured air flow, through the intermediate portion of the engine power operating range, in substantiallyithe following manner.

Air flowing through the Venturl throat l4 will produce a pressure differential in the channels 86 and 42 which differential is transferred to the opposite side of the diaphragm 46tending to force the diaphragm in a direction to open the valve 88. When the valve 80 is open fuel will flow from the line 66 through the valve into the space in the upper chamber 26 below the diaphragm 48 from where it will flow through the channel 52, and channel 58' to the fuel nozzle 22.- As the channel 58 is also connected with the space above the diaphragm 48, as long as there is fuel flow through the channel 68 a pressure differential will be set up upon the opposite sides of the diaphragm 48 by reason of the restriction 64. which pressure differential will have a tendency tomove the diaphragm 48 in a direction to close the valve 38. Thus the resultant of the pressure differential acting on the diaphragm 46 is in the opposite direction to the resultant of the pressure differential acting on the diaphragm 48. In operation the pressure differential acting on the diaphragm 46 moves the valve 88 and thereby adjusts the pressure differential acting on the diaphragm 48 until the resultants of these differential pressures are equal. At this time the stem 56 is at rest and the mechanism is effective to accurately balance the amount of fuel flowing through the orifice 54 to the amount of air flowing through the venturi H. In order that the only valve moving forces acting on the valve 38 shall be the resultants of the pressures acting on the diaphragms 46 and 48,

- the forces resulting from the pressures acting on the remaining elements on the stem 56 are balanced out as follows:

The channel 18 connects the space below the diaphragm 48 with the interior of the recess 58 and an additional channel 12 connects the space stem 56 which is balanced by the same pressure aperture; in the. partition 44 and through the opening of the .valve 88 .to a position below the valve-gate 34 and also extends at its upper end into arecess. 58 provided in the end wall of the chamber 26.= -A diaphragm 68, connected to the endmfstheshaft56, seals the inner end of the recess 58,.a'second diaphragm 62, connected to theslia'ft' seals the aperture through the partition 44-,raalid1ai third diaphragm 64, connected to the meter the fuel to the engine, in accordance with on that area in the space 58. The resultant of the difierence in pressures acting on the lower side of diaphragm 66 and the upper side of diephragm 62 is balanced by the resultant of the 'same difference in pressures acting on the lower side of diaphragm 62 and the upper side of diaphragm 68.

As the fuel metering device does not operate accurately at extremely low airflow rates through the venturi and extremely small throttle openings, an auxiliarymetering valve I4 cooperating with the'oriflce 54 and operated by a connection 16 with the throttle-l6, is provided to meter the fuel during engine idling operation. a

A fuel economizer, generally indicated at 18, may also be incorporated to richen the fuel mixture above a predetermined point in the engine 84 by a compression spring 86. The spaces provided bythe diaphragms 82, 84 and 86 are connected with the spaces at the opposite sides of the main diaphragm 4 6 in such a manner that when the pressure differential exerted on this main diaphragm exceeds a predetermined value in a direction to open the valve 30 the corresponding pressure differential on the economizer diaphragms will become suflicient to compress the spring 96 and open the valve 92 to admit additional fuel through this valve from the space below the diaphragm 48 to the space in the struction and' operation of a suitable fuel metering device, idling range control and economizer reference may be had to United States application Serial No. 302,749 for Fuel control devices,

filed November 3, 1939, by Guy E. Beardsley, Jr.

The lower portion of the chamber 28 is sealed oil by a transverse diaphragm 98 and from this diaphragm a shaft I extends downwardly in the chamber to 'a second diaphragm I02 below which the end of the shaft I00 rests upon a compression spring I04 the lower end of which is'carried upon an adjustable abutment I06. Between the diaphragms 98 and I02 the stem carries a valve gate I08 which cooperates with a seat formed around an aperture in a transverse partition IIO to constitute a valve generally indicated at I I2. A secondary fuel line II4. connects with a channel IIB leading into thespace between the partition H0 and the diaphragm I02 and a channel II8 leads through a conduit.l20 including. a restricted orifice I22 from the space between the partition I I0 and the diaphragm 98 to the channel 50.

The pressure on the fuel in the space in the chamber 26 below the diaphragm 48 will be transmitted through the passage I2 to the space in the lower chamber 28 between the diaphragms 04. and 98.

The pressure on the fuel in the line 50, as long as there is no fuel flowing in the line H8, is

transmitted through the passages H8 and I20. The pressures acting on the diaphragm I02 balance the pressures acting on the valve I08 in a manner similar to the way the pressures on the When this point is reached and the force of the spring I04 is overcome and thevalve'llz begins to open,.auxiliary fuel will flow from the line II4 through the valve I08, and channel II8, to the channel 50 where it will mix with the regular fuel being fed to the nozzle 22.

Regardless of the differential pressure acting on the diaphragm '48, the diiferentialpressure acting on the diaphragm 98 will'not increase materially above the pressure required to open the valve H2. The increase in differential pressure will depend only on the spring rate of the spring I04 and the extent to which the valve I I2 must be opened to maintain that differential pressure. The difference between the pressures acting upon the diaphragm 4G and the pressures acting upon the diaphragm 98 in these higher values will be accounted for by the pressure drop across the orifice I22. This drop will, of course,

be substantially proportionateto the increase in differential pressure above the predetermined amount so that the fuel flow will be accordingly proportioned to this increase in differential pressure and hence to the increase in airflow.-

If desired, the spring I04 may be so adjusted and the value of spring 96 of the economizer I8 so chosen that the valve II2 will open to supply auxiliary fuellto the engine when the economizer valve 92 opens to richen the engine fuel for extremely high power operating conditions. It is not necessary, however, that there be any deflnite cooperation between the economizer and the auxiliary fluid supply.

The auxiliary fuel and the anti-detonating substance may, if desired, be so chosen that the economizer may be dispensed with and the auxiliary valve I08 relied upon to perform the entire functions of supplying additional fuel for economizer action and for supplying an antidetonatingsubstance.

' reaching the carburetor discharge jet or the invalve 80 are balanced by the pressures on the diaphragm 84 of the main fuel supply except that in this case, the pressure on the area'of the stem I00 does not have a force opposing it," but in effect adds to the pressure acting on the lower side of the diaphragm 98. It will thus be seen that the flow responsive force tending to move the valve I08 is the product of the area of diaphragm 98 and the difference in pressures acting on the diaphragm 98 which diflerence, as has been pointed out above, is the same as the difference in pressures acting upon the diaphragm 48 and which in tum is the same as the difference in the pressures acting upon the diaphragm .46.

The force on the diaphragm 98 tends to open the valve I08 and is opposed by the spring I04 supported by the adjustable abutment. I06 The abutment I08 is adjusted to maintain the valve I08 closed until the difference in the pressures acting on the diaphragm 98 exceeds a predeter-' mined. value. As this differential pressure is the jection nozzle in order that the detonation reducing fluid may be distributed evenly with the main.fuel to all of the engine cylinders. With this arrangement, if there is a good distribution of the main fuel, there will be an equally good distribution of the mixture of the main fuel and the auxiliary fluid and the detonation inhibiting tendency will be applied equally to all of the engine cylinders.

' Any suitable manually actuatable means may be provided to open the valve I08 against the valve closing force of the spring I04 when it is desired to inject the auxiliary fuel for de-icing the intake passages or for other purposes, when same as the differential pressure of the airflow measuring mechanism, it is at once apparent that the valve H2 is maintained-closed until the airflow to the engine exceeds a predetermined amount which would be the point in the engine power operating range at which it is desired to begin the injection of auxiliary fuel or a fuel modifying substance.

the engine is not operating 'at sufficient power to cause an automatic injection of said auxiliary fuel in sufficient quantity.

In the arrangement illustrated, a shaft I23 projects through the casing 24 and causes at its inner end a cam I25 which is positioned overthe upper end of the stem I00. A lever arm I28 is connected to the end of the shaft 123 outside of the casing 24 and a manually operable linkage,

' asindicated at I28, is connected to the free end of the lever to rotate the shaft I23 under manual actuation and cause the cam I25 to bear against the upper end of the stem I00 and open the valve.

While a suitable mechanical arrangement has been illustrated in the accompanying drawing and hereinabove described for the purpose of disclosing the invention, it is'to be understood that the invention is not limited to the particular arrangement so illustrated anddescrlbembut that-suchchanges in the illustrated arrangement may be resorted to as come within the scope of the sub- Joined claims.

Having now described the invention so that others skilled in the'art may clearly understand the same, what it is desired to secure by Letters Patent is as follows:

1. An engine fuel supply system comprising,

an air intake, a venturi in said intake for measuring the quantity of air flowing therethrough, a fuel supply line, means responsive to the airflow through said venturi and the fuel flow through said supply line for proportloning the quantity of fuel to the quantity of air, a nozzle for injecting said fuel into the air stream, an economizerdevice for increasing the proportion of fuel in the fuel-air mixture whenever the quantity of air flow exceeds a predeterminedvaiue, means for introducing an anti-detonation ingredient other than said fuel into the fuel supply ahead of said discharge means, means for withholding and controllingthe flow of said ingredient including a valve, and fuel pressure responsive means for ac tuating said valve in accordance with the quantity of air flowing through said venturi,

. 2. An engine fuel, supply system comprising, an air intake, a venturi in said intake for measuring the quantity of air flowing therethrough, a fuel supply line, a restricted orifice in said line, means responsive to the airflow through said venturi and the fuel flow through said orifice establishing a fuel pressure differential across said orifice which is a function of said airflow for proportioning the quantity of fuel to the quantity of air, means for discharging said fuel into the airstream, an economizer device for increasing the proportion of fuel in the fuel-air mixture over the higher power portion of the engine power range, means for introducing into said airstream an anti-detonation ingredienthaving a composition difl'erent from said fuel, and means for metering the quantity of said ingredient so introduced comprising a valve and means for actuating said valve in accordance with variations in said pressure differential to substantially proportion the quantityzof ingredient to the quan tity Of all.

3. In an engine fuel supply system, an airintake, a venturi in said intake for measuring the venturi and the fuel flow through said fuel restriction formaintaining a fuel pressure differential across said fuel restriction which is a function of the quantity of said airflow, a fluid intake for introducing an ingredient having a composition different from said fuel into said air, an ingredient flow restriction in said ingredient intake for establishing an ingredient pressure differential for metering the flow of said ingredient, and valve means'respousive to variations in said fuel pressure diflerential for varying said ingredient pressure differential in accordance with variations in said fuel pressure differential.

4. In a charge forming apparatus for an internal combustion aircraft engine having an air intake, the combination comprising, a fuel flow regulating device including a fuel supply line for introducing fuel under pressure into the engine charging air and a fuel mete ingorifice in said fuel line, a liquid supp y line for introducing an ingredient having a composition different from said fuel into the engine charging air, an ingredient metering orifice in said ingredient line, said .fuel line and said ingredient line being connected on the lower pressure sides of said orifices, and means for regulating the pressure of the ingredient on the higher pressure side of said ingredient orifice comprising an ingredient flow controlling device in said ingredient line and means subjected to the pressure of said fuel on the higher pressure side of said fuel orifice and the pre's- DONALD S. I-IERSEY. ARTHUR E. SMITH. 

